REST API: Support . in theme directory names in WP_REST_Global_Styles_Controller, WP_REST_Templates_Controller, and WP_REST_Themes_Controller.

Regex changes from [52376] are reverted to restore the original regex patterns. Why? [52376] used an include characters pattern, which was too limiting. It did not account for localized characters, such as `é`, or other valid directory name characters.

The original theme directory regex pattern, i.e. `[^.\/]+(?:\/[^.\/]+)?` excluded the period `.` character. Removing the `.` character resolves the reported issue by allowing matching for `themes/theme-dirname-1.0/` or `themes/<subdirname>/theme-dirname-1.0/`.

As the pattern used an exclude approach, all characters are valid for matching except for `/`. However, not all characters are cross-platform valid for directory names. For example, the characters `/:<>*?"|` are not valid on Windows OS. The pattern now excludes those characters.

The theme's directory (or subdirectory) name pattern matching is now used in `WP_REST_Global_Styles_Controller`, `WP_REST_Templates_Controller`, and `WP_REST_Themes_Controller`.

Follow-up to [51003], [52051], [52275], [52376].

Props costdev, hellofromTonya, spacedmonkey, TimothyBlynJacobs, bijayyadav, kafleg.
Fixes #54596.

git-svn-id: https://develop.svn.wordpress.org/trunk@52399 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/theme/themeDir.php

@@ -163,6 +163,8 @@ class Tests_Theme_ThemeDir extends WP_UnitTestCase {
 			'REST Theme',
 			'Block Theme',
 			'Block Theme Child Theme',
+			'Block Theme [0.4.0]',
+			'Block Theme [1.0.0] in subdirectory',
 		);
 
 		sort( $theme_names );